The present work describes a synthesis route for bulk Ta 4 AlC 3 MAX phase ceramics with high phase purity. Pressure-assisted densification was achieved by both hot pressing and spark plasma sintering of Ta 2 H, Al and C powder mixtures in the 1200–1650 °C range. The phases present and microstructures were characterized as a function of the sintering temperature by X-ray diffraction and scanning electron microscopy. High-purity α-Ta 4 AlC 3 was obtained by hot pressing at 1500 °C for 30 min at 30 MPa. The β-Ta 4 AlC 3 allotrope was observed in the samples produced by SPS. The Young's modulus, Vickers hardness, flexural strength and single-edge V-notch beam fracture toughness of the high-purity bulk sample were determined. The thermal decomposition of Ta 4 AlC 3 into TaC x and Al vapour in high (˜10 −5 mbar) vacuum at 1200 °C and 1250 °C was also investigated, as a possible processing route to produce porous TaC x components.
|Number of pages
|Journal of the European Ceramic Society
|Early online date
|8 Apr 2019
|Published - 1 Aug 2019